Managed-pressure cementing provides zonal isolation in deepwater Gulf of Mexico

Managed-pressure cementing (MPC) is an important technique for primary cementing operations in wells with narrow pressure margins between the pore and fracture gradients. This paper presents the design considerations, methodology, and results of two deepwater MPC operations conducted to cement production casing strings within a target operating window of approximately three-tenths of a pound. Modern transient hydraulic modeling software permits the calculation of adequate surface pressure levels to control the annular pressure profile during the different stages of a cementing operation. On the basis of a predetermined annular pressure target, different variables can be designed to produce surface and downhole pressures within existing limits of a particular operation. This capability, combined with modern managed-pressure-drilling (MPD) systems, enables accurate control of the annular pressure profile during cementing and makes it possible to obtain near-constant bottomhole pressure (BHP) throughout the cement placement operation while using statically underbalanced mud columns. © 2019 Society of Petroleum Engineers. All rights reserved.